3 files changed, 29 insertions, 0 deletions
diff --git a/target/s390x/helper.h b/target/s390x/helper.h
index 577edb384f..e2710f4fb3 100644
--- a/target/s390x/helper.h
+++ b/target/s390x/helper.h
@@ -123,6 +123,7 @@ DEF_HELPER_4(cu42, i32, env, i32, i32, i32)
 DEF_HELPER_5(msa, i32, env, i32, i32, i32, i32)
 DEF_HELPER_FLAGS_1(stpt, TCG_CALL_NO_RWG, i64, env)
 DEF_HELPER_FLAGS_1(stck, TCG_CALL_NO_RWG_SE, i64, env)
+DEF_HELPER_FLAGS_3(probe_write_access, TCG_CALL_NO_WG, void, env, i64, i64)
 
 /* === Vector Support Instructions === */
 DEF_HELPER_FLAGS_4(vll, TCG_CALL_NO_WG, void, env, ptr, i64, i64)
diff --git a/target/s390x/internal.h b/target/s390x/internal.h
index 07b69b8ea0..3b4855c175 100644
--- a/target/s390x/internal.h
+++ b/target/s390x/internal.h
@@ -349,6 +349,8 @@ void ioinst_handle_sal(S390CPU *cpu, uint64_t reg1, uintptr_t ra);
 
 /* mem_helper.c */
 target_ulong mmu_real2abs(CPUS390XState *env, target_ulong raddr);
+void probe_write_access(CPUS390XState *env, uint64_t addr, uint64_t len,
+                        uintptr_t ra);
 
 
 /* mmu_helper.c */
diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c
index a506d9ef99..3f76a8abfd 100644
--- a/target/s390x/mem_helper.c
+++ b/target/s390x/mem_helper.c
@@ -2623,3 +2623,29 @@ uint32_t HELPER(cu42)(CPUS390XState *env, uint32_t r1, uint32_t r2, uint32_t m3)
     return convert_unicode(env, r1, r2, m3, GETPC(),
                            decode_utf32, encode_utf16);
 }
+
+void probe_write_access(CPUS390XState *env, uint64_t addr, uint64_t len,
+                        uintptr_t ra)
+{
+#ifdef CONFIG_USER_ONLY
+    if (!h2g_valid(addr) || !h2g_valid(addr + len - 1) ||
+        page_check_range(addr, len, PAGE_WRITE) < 0) {
+        s390_program_interrupt(env, PGM_ADDRESSING, ILEN_AUTO, ra);
+    }
+#else
+    /* test the actual access, not just any access to the page due to LAP */
+    while (len) {
+        const uint64_t pagelen = -(addr | -TARGET_PAGE_MASK);
+        const uint64_t curlen = MIN(pagelen, len);
+
+        probe_write(env, addr, curlen, cpu_mmu_index(env, false), ra);
+        addr = wrap_address(env, addr + curlen);
+        len -= curlen;
+    }
+#endif
+}
+
+void HELPER(probe_write_access)(CPUS390XState *env, uint64_t addr, uint64_t len)
+{
+    probe_write_access(env, addr, len, GETPC());
+}